On Thursday 27 November 2014 21:39:42 Rafael J. Wysocki wrote: > On Thursday, November 27, 2014 09:01:11 PM Pali Rohár wrote: > > --nextPart2712852.Yg3XtZvm05 > > Content-Type: Text/Plain; > > > > charset="utf-8" > > > > Content-Transfer-Encoding: quoted-printable > > > > Hello, > > > > on 3.18-rc5 I have empty cpu uevent file, but modalias file > > is=20 populated. See: > > > > $ cat /sys/devices/system/cpu/uevent=20 > > $ cat /sys/devices/system/cpu/modalias=20 > > cpu:type:x86,ven0000fam0006mod003C:feature:,0000,0001,0002,0 > > 003,0004,0005,0= > > 006,0007,0008,0009,000B,000C,000D,000E,000F,0010,0011,0013, > > 0015,0016,0017,0= > > 018,0019,001A,001B,001C,001D,001F,002B,0034,003A,003B,003D, > > 0068,006B,006C,0= > > 06D,006F,0070,0072,0074,0075,0076,0078,007C,007D,0080,0081, > > 0082,0083,0084,0= > > 085,0086,0087,0088,0089,008B,008C,008D,008E,008F,0091,0093, > > 0094,0095,0096,0= > > 097,0098,0099,009A,009B,009C,009D,009E,00C0,00C5,00E0,00E1, > > 00E3,00E5,00E6,0= > > 0E7,0100,0101,0102,0103,0104,0120,0121,0123,0124,0125,0127, > > 0128,0129,012A,0= 12B,012D,0140 > > > > =46or all other devices in /sys/devices/ which have > > modalias=20 content there is also MODALIAS=3D line in > > uevent file. > > /sys/devices/system/cpu/ is not a device. It is a "collection > of all CPUs". > Ok. But why that inconsistency (missing MODALIAS line)? > > Is cpu device special? Or why it is only one device which > > has=20 modalias file but is missing MODALIAS=3D line in > > uevent file? > > Look into the uevent files under /sys/devices/system/cpu/cpu0/ > etc. > $ cat /sys/devices/system/cpu/cpu0/modalias cat: /sys/devices/system/cpu/cpu0/modalias: No such file or directory $ cat /sys/devices/system/cpu/cpu0/uevent DRIVER=processor MODALIAS=cpu:type:x86,ven0000fam0006mod003C:feature:,0000,0001,0002,0003,0004,0005,0006,0007,0008,0009,000B,000C,000D,000E,000F,0010,0011,0013,0015,0016,0017,0018,0019,001A,001B,001C,001D,001F,002B,0034,003A,003B,003D,0068,006B,006C,006D,006F,0070,0072,0074,0075,0076,0078,007C,007D,0080,0081,0082,0083,0084,0085,0086,0087,0088,0089,008B,008C,008D,008E,008F,0091,0093,0094,0095,0096,0097,0098,0099,009A,009B,009C,009D,009E,00C0,00C5,00E0,00E1,00E3,00E5,00E6,00E7,0100,0101,0102,0103,0104,0120,0121,0123,0124,0125,0127,0128,0129,012A,012B,012D,0140 So there is no modalias file, but uevent contains MODALIAS line. > > What userspace application should use for reading > > modalias=20 string? File modalias or file uevent? > > The cpu modalias is used to trigger loading of some > CPU-specific modules upfront IIRC. So yes, it is special. > > My advice would be to follow udev here. Yes, I know. For some reasons coretemp.ko is not automatically loaded. I do not know why and I started investigating it. And I found above inconsistency in modalias and uevent... $ modinfo coretemp ... alias: cpu:type:x86,ven0000fam*mod*:feature:*00E7* -- Pali Rohár pali.rohar@xxxxxxxxx
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